That's the
"Rule of 45". It breaks the basic strategy
down into finer detail. You should do this even
with eight decks, although the fewer the decks,
the more difference it makes. A classic stand situation
would be a 16 made up of 7/5/4 since it contains
both a 4 and a 5! You don't need to have both though.
You should also stand against a 10 with hands like
9/5/2 or 4/3/9 -- anything that contains a 4 or
a 5. But if you've built something like an A/6/8/A,
you should still hit because you haven't drawn any
cards out of play that would have done much for
your hand. Here are two vivid pictures to illustrate
the Rule of 45 in action:

Probably
make better use of a 7 or a S -- than a 10 or a
deuce. That double flip-flop is enough to make hitting
your 10/2 better than standing -- unless it's an
eight deck games! At eight decks is where such a
fine distinction washes away. But with one through
six decks, follow the "Dr. Pepper Rule.

Ironically
for most players, this kind of acting is reflexive.
Feigning strength or weakness is not a characteristic
of a good card player; feigning them 2cell is a characteristic
of a good card player. The greater the drama and the
greater the unnecessary talk, in whatever direction,
the more you need to be attuned to the deception that
is being attempted. III these situations, you can
make a lot of money if you play according to Caro's
injunction that players who act weak are usually strong,
and players who act strong are usually weak.;'

The utility of involuntary tells, on the other hand,
is much more dubious at a home game. The reason is
that the relatively low stakes of typical home games,
combined with the social atmosphere and high blood
alcohol levels, reduces the tension that underlies
most involuntary tells. You could easily find yourself
trying to read an opponent who cares more about who
is going to get the last Guinness than the fact that
he's holding the nut flush.